BIDIRECTIONAL MAXIMUM LIKELIHOOD SERIES ESTIMATION SYSTEM

摘要

PURPOSE: To avoid a burst error by monitoring the deterioration of communication quality, selecting optimum forward maximum likelihood series estimation processing and backward maximum likelihood series estimation processing and switching the processing, and to compose a receiver having a low code error rate characteristic. ;CONSTITUTION: Reception signal series 10 are inputted in the maximum likelihood series estimation processing part 11 of the forward direction along a time axis and the maximum likelihood series estimation processing part 13 of the backward direction which is delayed by a slot delay block 12 and is reverse to the time axis. Next, the absolute value 16 of the forward direction transmission line impulse response estimated in the processing part 11 is defined as a communication quality evaluation reference and the communication quality of the forward direction is always evaluated in a communication quality evaluation processing part 18. When the communication quality is not deteriorated, the processing result 14 of the processing part 11 is defined as the final estimation series 111. When the communication quality is deteriorated, a control signal 19 is transmitted to the processing part 13 and the processing of the back ward direction is made to be performed. Thus, a burst error can be avoided and an inadvertent erroneous code can be relieved due to the delay of the recovery from an erroneous propagation.;COPYRIGHT: (C)1996,JPO